Screw-tap



(No Model.) I

A. J. PEAVEY sousw TAP.

No; 295,421 Patented Mar. 18, 1884.

UNITED STATES ATENT @rricn.

ANDREW J. PEAVEY, OF 'SOMERVILLE, ASSTGNOR TO HIMSELF AND EDWIN B. BUGKINGHAM, OF BBOOKLIN E, MASSACHUSETTS.

SCREW-TAP.

SPECIFICATION forming part of Letters fatent No. 295,421, dated March 18, 1884:.

Application filed May 1, 1883. (No model.)

To aZZ whom it may OOH/087771! Be it known that I, ANDREW J. PEAVEY, of Sonierville, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Screw-Taps,

of which the following is a full, clear, and exact description. This improved screw-tap in substance is composed of an arbor, of a sleeve surrounding said arbor, containing aseries of radial screwcutting dies, and-of two sets of cams or scrolls, all so that by turning said arbor in one direction said screw-cutting dies will be forced outwardly, or from the center of said arbor, and I 5 in turning said arbor in the other and opposite direction said screw-cutting dies will be drawn inwardly toward the center of said arbor, substantially as hereinafter described.

In the accompanying plate of drawings this improved screw-tap is illustrated.

Figure 1 is a side view; Fig. 2, a cross-section on line 2 2, Fig. 1; Fig. 3, a central longitudinal section on line 3 3, Fig. 2; Fig. 4, a crosssection on line 4 4, Fig. 3; Fig. 5, acentral longitudinal section on line 5 5, Fig. Fig. 6, a or oss-section on line 6 6, Fig. 1; Figs. 7 and S, longitudinal sectional views, to be hereinafter particularly referred to.

In the drawings, Arepresents an arbor having along a portion of its length similar scrolls creams or eccentric surfaces, B, relative to the axis of the arbor. These scrolls B are an ranged at equal distances apart and regularly around the arbor, giving a series of shoulders or abutments, 0, between the innermost end, a, of one scroll and the outermost and next adjoining end, i), of another and the next scroll in the order of arrangement. The scroll portion of the arbor A, and at each end thereof,

40 has a collar, D, and each collar D has four scroll or cam slots, E, corresponding to the scrolls Bof the arbor, and which latter scrolls, B, continued constitute the inside walls of said slots. These collars D are fastened to the ar- 1101 A by pins G, or otherwise, so as to be attachable and detachable at pleasure, and between them and surrounding the arbor is a sleeve, F, having along its length, for a portion thereof, radial slot-s G, at equal distances 5o apart, in each of which is located a screw-cut ting die, H, having an outer screw-cutting face or edge, (I, and an inner smooth face or edge, f, to bear against a scroll, B, of the arbor A, and extensions 5/ at each end, to enter into the cam or scroll slots of the collars D at each end of the scroll portion of the arbor.

1 Ascrew-tap constructed as described, placed in the hole to be screw-tapped, is turned around therein in a direction for the scrolls of the arbor to force the screw-cutting dies outward and from the center or axis of the arbor, and thus secure the cutting of the screwthread in said hole, as desired. Turning the screw-tap in the opposite direction to that above described secures, through the action of the scroll-slots Eupon either end of the screwcutting dies, an inward movement of the said dies-that is, a movement toward the center or axispf the arbor-thus.withdrawing them from action upon the hole.

The cam-slots E, at either end of the scrollarbor, may be dispensed with; but it is preferable to use them, and to have one at each end, and to engage the cutting-dies with both of them, for the reason that by'their act-ion the 7 5 screw-cutting dies will be positively drawn in when the arbor is turned in the proper direction therefor.

A screw-tap made as particularly shown in Figs. 1 to 6, and to which figures the precedmi; description applies, owing to the fact that the screw'cutti ng dies are between thetwo ends of the tool and do not extend fully up to one end thereof, is not capable of screw-tapping a socket or hole closed at one end up to said end; but in Figs. 7 and 8 a tool substantially of the construction hereinbcfore described, but varying in some respects therefrom, is illustrated which is capable of screw-tapping a socket or hole closed at one end. In said Figs. 7 and 8 parts corresponding with those shown in the previous figures are lettered as before-as, for instance, A is the scrolled arbor. H are the radially-moving screw-cutting dies. F is the sleeve surrounding them, having vertical ra- 5 dial slots G for said screw-cutting dicsH; and D is the scrolled collar for forcing the screwcutting dies in toward the axis of the scrolled arbor. Each screw-cutting die extends to the extreme end of the scrolled arbor A, and, as

shown in Fig. 7 the surrounding sleeve F covers only a portion, m, of the length of each die H, and leaves the screw-cutting portion a of each exposed. The arbor has a peripheral groove, Z, which receives the internal annular collar, L, of the sleeve. and the sleeve has radial slots G, each of which receives the lug M of a screw-cutting die, H, and all so that the sleeve and the dies are retained upon the arbor, and yet as the arbor is turned, forcing by its scrolls E the cutting-dies outward or allowing them to travel inward, said sleeve is free to accommodate itself to such movement of the dies by turning with the dies upon the arbor. The scrolled collar D loosely surrounds the sleeve F, and has its scrolls to force the dies inward located therein in suit able position to act upon the outer ends, 0, of the lugs M of the dies before referred to, said lugs being made of suitable radial length therefor. Said collar is screwed upon the arbor and there fastened by a check or set nut, s, also screwed upon the arbor.

In Fig. 8 the sleeve F, having radial slots G, surrounds the cutting-dies H in their portion having cutting-edges, and also in their straight portions, substantially the same as in the screw-tap of thepart-icular construction shown in Figs. 1 to 6, inclusive.

The sleeve and also the dies are retained upon the arbor bya cap-plate, N, fastened by a screw, 1), to the extreme end of the arbor A. The cutting-dies extend across the edge or periphery of this cap-plate N, and at such part are cut out, as at g, on their inner edge; and the cap-plate is of a suitable size or diameter to allow the dies their desired movement outward from the action thereon of the scrolls of the arbor A, and their desired movement inward from the action thereon of 0 the scrolls or cam-slots of the collar D, attached to or a part of the arbor, said collar being at the inner end of the sleeve.

In all the forms of tools which have been illustrated and described it is obvious that there are the same separate elements or parts, and that, except slight modifications in construetion to accommodate said elements or parts to the end to be attained, they are combined and arranged and operate together in substantially the same manner.

Having thus described my invention, What I claim, and desire to secure by Letters Patent, 1s

1. A screw-tap composed of an arbor, A, carrying a cam-slotted collar or collars, D, and of a slotted sleeve, F, having screw-cutting dies H, constructed and arranged together substantially as described, for operation as specified.

2. A screw-tap composed of an arbor, A, having scrolls B, and a cam-slottedcollar or collars, D, and of a slotted sleeve, F, having screw-cutting dies H, constructed and arranged together substantially as described, for the purpose specified.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

A. J. PEAVEY.

WVitnesscs:

EDWIN W. BROWN, XV. S. BnLLows. 

